The present exemplary embodiments relate generally to lighting. They find particular application in conjunction with traffic lamps, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiments are also amenable to other like applications.
Traffic signals are typically disposed along roads to control the flow of traffic and/or make intersections more visible. Traffic signals may also be employed to provide warning to motorists, such as at railroad crossings. Traffic signals may include one or more traffic lamps, each having one or more light sources, such as LEDs, disposed therein. Typical colors used in traffic lamps include red, yellow and green.
One problem with traffic lamps is that light sources, such as LEDs, may degrade with temperature and age. In other words, the light output of a light source may diminish with temperature and age. Reduction in light output can make traffic signals less noticeable, thereby increasing the likelihood of accidents.
Known solutions to this degradation only compensate for temperature degradation. Namely, known solutions can maintain light output at a constant level through the operating temperature range of a traffic lamp, but they cannot maintain light output at a constant level through the lifetime of a traffic lamp. As a general matter, this is because known solutions are lacking monitoring and/or logging capability of operating parameters. They cannot track the usage of a traffic lamp.
Another problem with traffic lamps is that they are often used improperly outside of the operating specifications, which can lead to overheating and/or malfunction. Overheating can cause numerous problems, which places the safety of motorists at risk. For example, in situations in which a traffic lamp is used to make an intersection more visible and/or control the flow of traffic, a failure of the traffic lamp can lead to collisions.
Known solutions to this misuse of traffic lamps use passive circuits to mitigate overheating and/or malfunction. However, there are limitations with using passive circuits to mitigate overheating. For example, passive circuits cannot take affirmative action to avoid overheating and/or malfunction. As another example, passive circuits generally cannot log and/or monitor the operating conditions of a traffic lamp.
Another problem with traffic lamps is that they often reach the end of their life without any indication to an operator thereof. End of life means a traffic lamp has reached the point where light output can no longer be guaranteed. Similar to improperly using a traffic lamp, failure to replace a lamp when it reaches the end of its life can be dangerous.
Known solutions to this problem use a light sensing device in order to sense degradation of a traffic lamp. When light is detected below a certain level, a circuit blows an input fuse. However, blowing the fuse completely disables the lamp until the fuse is replaced, notwithstanding that it may have still be working, albeit at a less than optimal level. Further, blowing the fuse requires replacement of what may have been a perfectly good fuse.
The present disclosure contemplates new and improved systems and/or methods for remedying this and other problems.